Help installing toilet flange

I am installing a toilet flange on top of a new tile floor in a half bathroom. Due to the way the joists are laid out under this bathroom I had to do a 10" rough in for the toilet. Its more like 9.5" to 9.75" rough in (if I jam the pipe all the way against the joist). I bought a Toto Carlyle II toilet with 10" unifit adapter based on recommendations from this forum. I am planning to do half inch thick pine trim in the bathroom with shoe molding. I am concerned that there will not be enough room for this trim behind the toilet. I have attached pictures. Here are my questions:

1) At 9.75" RO how much space behind the Carlyle will I have for trimwork?

2) I picked the 4x3 stainles steel/PVC toilet flange but I wasn't really thinking when I bought it. I guess if I picked a 3" toilet flange I may have actually reached a 10" rough-in. Now it is kind of late to go back to 3" toilet flange since i cut the hole in the tile for a 4" flange. Do you guys think the 4x3 flange I chose is a good pick or should I try to use a 3" flange?

3) How should I install the flange? I'm not really sure how to orient it. I am guessing where the bolts go should be facing left and right from the wall. I am planning to use diamond drill bits to drill the holes and use stainless steel deck screws to hold the flange down to the subfloor. Does this sound good?

4) How many screws do I need to put into the flange at a minimum for a good install? All 6?

5) Do you guys foam or caulk under the flange to fill the hole in the subfloor?

WHen using the T-slots, you want the small end of the slot on either side to be at the flange rough-in distance, or maybe with a slight amount of room to the end of that slot. This is the strongest part of the slot. The SS ring is good. The flange you have has a socket on the bottom. This means you need to measure carefully to get the riser length proper so the pipe gets seated, and isn't too long or too short. They do make a similar flange that is more like a coupling...the pipe can be left long, the flange slid over it, then the pipe is cut off flush with the top of the flange when you're done. What you have will work fine, but measure carefully (you cannot dry fit, as the pipe won't bottom in the sockets until it melts with the cement). The Carlyle typically has about 3/4" clearance behind it when the rough-in is exact. There's more room at the base, so you shouldn't worry about a typical baseboard...only if it were very thick. When you install the Unifit adapter, you can fudge it forward maybe 1/4" or so from being exactly centered on the flange if you need it, but you probably won't. You do not want to be applying stress to the drain pipe. If you can't make it work, you may need to redo the pipe.

WHen using the T-slots, you want the small end of the slot on either side to be at the flange rough-in distance, or maybe with a slight amount of room to the end of that slot. This is the strongest part of the slot. The SS ring is good. The flange you have has a socket on the bottom. This means you need to measure carefully to get the riser length proper so the pipe gets seated, and isn't too long or too short. They do make a similar flange that is more like a coupling...the pipe can be left long, the flange slid over it, then the pipe is cut off flush with the top of the flange when you're done. What you have will work fine, but measure carefully (you cannot dry fit, as the pipe won't bottom in the sockets until it melts with the cement). The Carlyle typically has about 3/4" clearance behind it when the rough-in is exact. There's more room at the base, so you shouldn't worry about a typical baseboard...only if it were very thick. When you install the Unifit adapter, you can fudge it forward maybe 1/4" or so from being exactly centered on the flange if you need it, but you probably won't. You do not want to be applying stress to the drain pipe. If you can't make it work, you may need to redo the pipe.

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I am not sure what you mean about not being able to dry fit with the flange that I have. I was able to push the pipe into the flange and remove it. There are a few tabs that seem to stop the pipe about a couple of inches or so deep. Do you have a name or link to the other kind of flange you are talking about? Thanks.

A properly installed PVC pipe fitting has the pipe go all the way to the bottom of the socket. The socket is tapered. The bottom maybe 1/4-1/3 is smaller than the pipe's OD. So, if you push the pipe in until it stops, then measure, when you add the cement, which literally melts the plastic and push it to the bottom, the pipe will be short! You must measure the depth of the sockets, not try to dry fit or the pipe will be short, or the fitting won't end up where you want it. Found some that can fit inside of a 4" pipe, or over a 3" pipe, but not one that will fit over a 4" pipe. Pretty sure they make one...one of the pros may help in that regard. Also, if you don't weight it down, because the socket is tapered, until the cement's solvent evaporates, if you just leave it sit there, it can literally push itself apart. Either screw it down right away, or put something heavy on it until the cement cures. That depends on how much you put on, the temperature, and the size of the fitting. It's really annoying to not do this and come back in a half hour or so and find it rock solid, but now sitting 1/2" above the floor rather than on it!

It looks like you have a heel inlet to your closet bend. Where is that coming from and what is feeding into it? If this is a project that is going to be inspected, it's doubtful that that is going to pass inspection. Presumably you have a (min. 2") vent within a developed length of six feet from the flange (measured as if you stuck a tape measure down the flange and through the pipe...six feet maximum from the lip of the flange to the vent). To be to code, whatever that is that's flowing through the heel inlet should actually connect downstream of the vent for the closet flange, and the heel inlet eliminated. Doesn't mean people don't do it; just means it won't pass inspection.

As to your unanswered questions, your attachment approach sounds good. Best way to orient the flange is to measure from the wall in both places and, as Jim said, have the small end of the slot into which your closet bolts will slide be equidistant from the wall on each side. You can leave a little wiggle room; doesn't have to be right at the end. Since you are using a Unifit, you're not mounting the toilet to the flange anyway; you're mounting the Unifit to it and you will use the closet bolts and wax to make a nice seal between the Unifit and the flange. You will drill the floor and secure to the subfloor the end of the Unifit that is closest to the wall. The toilet will then "plug in" to the Unifit, and be bolted down to the Unifit.

Are six screws better than four when mounting? Probably.

You should have enough room behind the toilet base to use your 1/2" baseboard. I have a Carlyle II and some thick-ish baseboard. I would estimate about 1/2" difference between the rearmost part of the "tank" and the rearmost part of the base. You can always dry-fit it to be sure.

Looking at your photos...always kind of freaky to realize how little is standing between us and the kitchen floor below.

The inlet into the closet bend is coming from the bathroom sink. The toilet is closest to the main stack. The sink is further away. The toilet is less than 2' from the 4" stack pipe which of course is vented. Is this considered incorrect? I am pretty sure this is how it was built originally but I cannot remember what the original plumbing looked like.

This bathroom is on the first floor. What you see below is the basement.

It looks like you have a heel inlet to your closet bend. Where is that coming from and what is feeding into it? If this is a project that is going to be inspected, it's doubtful that that is going to pass inspection. Presumably you have a (min. 2") vent within a developed length of six feet from the flange (measured as if you stuck a tape measure down the flange and through the pipe...six feet maximum from the lip of the flange to the vent). To be to code, whatever that is that's flowing through the heel inlet should actually connect downstream of the vent for the closet flange, and the heel inlet eliminated. Doesn't mean people don't do it; just means it won't pass inspection.

As to your unanswered questions, your attachment approach sounds good. Best way to orient the flange is to measure from the wall in both places and, as Jim said, have the small end of the slot into which your closet bolts will slide be equidistant from the wall on each side. You can leave a little wiggle room; doesn't have to be right at the end. Since you are using a Unifit, you're not mounting the toilet to the flange anyway; you're mounting the Unifit to it and you will use the closet bolts and wax to make a nice seal between the Unifit and the flange. You will drill the floor and secure to the subfloor the end of the Unifit that is closest to the wall. The toilet will then "plug in" to the Unifit, and be bolted down to the Unifit.

Are six screws better than four when mounting? Probably.

You should have enough room behind the toilet base to use your 1/2" baseboard. I have a Carlyle II and some thick-ish baseboard. I would estimate about 1/2" difference between the rearmost part of the "tank" and the rearmost part of the base. You can always dry-fit it to be sure.

Looking at your photos...always kind of freaky to realize how little is standing between us and the kitchen floor below.

Does the sink have a vent? A vent must come off at the same level as the outlet of the trap arm BEFORE the drain line turns down, or it's not a vent...it's an S-trap. If it doesn't have a vent, then you need to do more work to give it one. THen, there are a couple of ways you could deal with this. One would be to put a wye in the 4" for the sink to drain into, but I'm sure there may be better ways to do this. As long as the sink gets vented properly, the toilet is close enough to the stack so you could probably get by with not venting it directly. But, another thing, the line going up, it's likely it is a drain line for things further up. The rules are, once a line becomes a drain, it is always a drain...once a vent, always a vent. A drain line can become a vent above the highest drain inlet. Older houses used the main stack as a vent for things because it was considered big enough. That isn't allowed anymore.

So you're saying if you touch your plumbing in an older house you'd have to radically redesign it to make it follow current code? If I am understanding you correctly I'd have to run a separate vent stack for this bathroom. The inspectors did not make the previous owner add another vent when they replaced the cast iron stack. Thank you.

Typically, you can repair what's there, but if you change things, the parts you touch must meet current code. The extent of the mods and the local inspector will determine what actually needs to be done. What was allowed way back when, obviously, can work, but it may not work in every situation, which is why the codes have evolved to try to accommodate. An old house may have been lucky to have one toilet, and now it's rare to find one without at least two, and many more isn't uncommon. Then, add a high efficiency washing machine that pumps MUCH faster than the old ones (but uses less water), and what worked with the 'old' methods no longer works. Lots of reasons why code changes, and the reason a repair is grandfathered, but changes are not.

It's interesting. I was focused more on the fact that you had the sink draining into a heel inlet on your closet flange, which isn't to code, assuming that your jurisdiction even requires/enforces codes. To be to code, the sink drain has to connect downstream of the vent from the closet flange, which in the current setup is the stack. I wasn't concerned that the sink wasn't vented properly, and the sink may indeed be vented properly to the stack through the wall on the floor above or otherwise. Does that stack have any fixtures from the floor above (or otherwise) draining into it at a level higher than you have shown in these photos, or is it purely a vent stack above there? If it's just a vent, and the sink's p-trap is vented to it somewhere, you're fine on the sink; that doesn't look to be more than 42" from the sink trap to the stack, horizonally, assuming that's a 1.5" drain.

The mere fact that they make closet bends with heel inlets indicates that people do plumb things this way, just not folks who are interested in having things done to code. I know some on here would say just to leave it alone, and that may be the right answer. But you can see how a clog in the pipe from the toilet to the stack, followed by plunging, could drive material back up the sink drain line and clog it with nastiness, or spew stuff up into the sink, which is probably one reason that the setup isn't code-compliant. But like I say, people do it. As this builder apparently did.

For what it's worth, here are two pretty-good pieces on plumbing for homeowners. The Bert Polk (Lincoln County) one is the one that Terry often cites to; the other one has some nice simplified diagrams and explanations that I have also found helpful.

The plumbers don't use a lo-heel outlet in that position. That's meant to be used in the vertical.
You can use a wye fitting after the 90 bend on the toilet and pick up the lav that way.
It would be closet flange, 90 bend, wye fitting and then toward the santee on your cast iron stack.

We don't really pay much attention to what we find. We try to do things an inspector would pass on an inspection with permits.

The Carlyle will need 9-1/4" from the finished wall to center with the 10" Unifit.
Floor mold will fit at the wall.

You can use a wye fitting after the 90 bend on the toilet and pick up the lav that way.
It would be closet flange, 90 bend, wye fitting and then toward the santee on your cast iron stack.

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Terry, just for my edification, I'm wondering about the vent. Bert seems to say that additional fixtures have to enter downstream of the vent for the toilet. If the stack is the vent for the toilet, wouldn't using a wye like this mean that the drain for the lav is entering the line upstream of the toilet vent? Particularly if the lav isn't itself properly vented (currently an open question), couldn't using a wye there cause the toilet to siphon the lav's P-trap? (Especially after he installs a Carlyle II?)

A properly installed PVC pipe fitting has the pipe go all the way to the bottom of the socket. The socket is tapered. The bottom maybe 1/4-1/3 is smaller than the pipe's OD. So, if you push the pipe in until it stops, then measure, when you add the cement, which literally melts the plastic and push it to the bottom, the pipe will be short! You must measure the depth of the sockets, not try to dry fit or the pipe will be short, or the fitting won't end up where you want it. Found some that can fit inside of a 4" pipe, or over a 3" pipe, but not one that will fit over a 4" pipe. Pretty sure they make one...one of the pros may help in that regard. Also, if you don't weight it down, because the socket is tapered, until the cement's solvent evaporates, if you just leave it sit there, it can literally push itself apart. Either screw it down right away, or put something heavy on it until the cement cures. That depends on how much you put on, the temperature, and the size of the fitting. It's really annoying to not do this and come back in a half hour or so and find it rock solid, but now sitting 1/2" above the floor rather than on it!

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The flange I have is designed to have the knockout plug removed after the flange is installed. The farthest I can probably get this pipe up is to the tabs right under where the knockout plug is. Is this wrong?

A heel inlet closet bend is never permitted to be installed with the inlet horizontal. This is specifically referenced in our plumbing code. Regardless that someone did it wrong many years ago, it is just as wrong today.

It also appears that you have installed a fernco style reducer over the hub on the sanitary tee, which is also improper. You need to use a fernco style donut in the hub to make the connection.

An alternative method of properly plumbing the water closet and the lav would be to replace the existing sanitary tee in the stack with one that has a side inlet, and then running the lav drain to the side inlet. In any case, the lav must have a vent, and this would have been true no matter what year the house was built.

A heel inlet closet bend is never permitted to be installed with the inlet horizontal. This is specifically referenced in our plumbing code. Regardless that someone did it wrong many years ago, it is just as wrong today.

It also appears that you have installed a fernco style reducer over the hub on the sanitary tee, which is also improper. You need to use a fernco style donut in the hub to make the connection.

An alternative method of properly plumbing the water closet and the lav would be to replace the existing sanitary tee in the stack with one that has a side inlet, and then running the lav drain to the side inlet. In any case, the lav must have a vent, and this would have been true no matter what year the house was built.

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If I remove the sanitary tee will the top of the stack fall down or are they usually secured? I'm not clear on how I would remove the tee without having to push the stack up to give sufficient clearance to remove the sanitary tee.